Congratulations, you have successfully completed this topic. You have learned how to determine the number of sides a regular polygon has, whether you are given the exterior angle or the interior angle of the polygon. You also explored tessellations. You can now identify a tessellation and are able to determine if a regular polygon will tessellate the plane. Lastly, you can find the measurement of the angle that is formed by adjacent angles. Angles are one of the key concepts of geometry, and you will continue to expand your knowledge of angles in other modules. Keep an eye out when you might have to apply your knowledge of interior or exterior angles.